A variety of different kinds of materials exist. However, there is a constant need for new and better materials, particularly for materials that have specific advantages in specific contexts, as well as for improved processes for manufacturing such materials.
For instance, different kinds of materials have been used in the construction of shoe soles. However, many of such materials have shortcomings, such as high manufacturing costs, high costs for raw materials and/or poor suitability for particular environments. In addition to these considerations, when manufacturing shoes abroad it is often desirable to minimize import duties or reduce costs resulting from use of carbon credits, which sometimes can be accomplished by appropriately constructing a shoe's sole. For instance, in many cases if at least 50% of the ground-contacting portion of the bottom surface of a shoe is a natural material, the shoe can qualify for a significantly lower United States import duty. See, e.g., chapter 64 of the Harmonized Tariff Schedule of The United States.